Researchers have developed a powerful imaging technique that reveals atomic scale defects inside computer chips for the first time. Using an advanced electron microscopy method, scientists from Cornell University mapped the exact positions of atoms inside tiny transistor structures and uncovered small imperfections nicknamed “mouse bites.”
These defects form during the complex manufacturing process and can disrupt how electrons flow through a chip’s channels, which are only about 15 to 18 atoms wide.
These tiny imperfections can interfere with chip performance, making them a major concern for modern electronics.
As well as involving Cornell researchers, the imaging technique was developed through a collaboration with Taiwan Semiconductor Manufacturing Company (TSMC) and Advanced Semiconductor Materials (ASM).
According to lead researcher Professor David Muller, who tells the Cornell Chronicle: “Since there’s really no other way you can see the atomic structure of these defects, this is going to be a really important characterisation tool for debugging and fault-finding in computer chips, especially at the development stage.”
Why this matters
Extremely small structural flaws have long challenged the semiconductor industry. As chips have grown more complex and their components have shrunk to the scale of individual atoms, even minor irregularities can affect how devices operate.
At the center of every computer chip is the transistor. This tiny component acts as a switch that controls the movement of electrical current. Each transistor contains a channel that opens and closes to regulate the flow of electrons.
“The transistor is like a little pipe for electrons instead of water,” Muller explains. “You can imagine, if the walls of the pipe are very rough, it’s going to slow things down. And so measuring how rough the walls are and which walls are good and which walls are bad is now even more important.”
Development curve
As chip technology has evolved, engineers tackled the issue of running out of surface area by stacking transistors vertically, creating complex three-dimensional structures that resemble high-rise apartment buildings. The problem is these 3D structures are smaller than the size of a virus, and hence subject to flaws. At this point, it matters where every atom is.
Atomic-level measurements
Muller has led a development in electron ptychography. This computational imaging technique relies on an electron microscope pixel array detector (EMPAD), a technology co-developed by Muller’s research group. The detector records detailed patterns created as electrons pass through the transistor structures.
Electron ptychography is a powerful computational imaging technique that enables high-resolution imaging and phase retrieval in electron microscopy, surpassing conventional resolution limits.
By comparing how these scattering patterns shift from one scan point to another, researchers can reconstruct extremely detailed images. The system is so precise that it has produced the highest resolution images ever captured, allowing scientists to see individual atoms with extraordinary clarity. This is a capability recognised by Guinness World Records.
Output
The researchers have succeeded in collecting and reconstructing the imaging data, and they have tracked the positions of atoms within the transistor channels. This analysis reveals subtle roughness at the interfaces of these channels. Karapetyan described these irregular patterns as “mouse bites.”
The defects formed during the optimized growth process used to manufacture the structures. Sample devices created at the nanoelectronics research center Imec provided an ideal platform for testing the imaging technique.
The ability to directly observe atomic-level defects could affect nearly every device that relies on advanced computer chips, including smartphones, laptops, and large data centres.
Furthermore, since computer chips power devices ranging from smartphones and cars to AI data centres and quantum computers, the discovery could influence many areas of technology.
The research appears in the journal Nature Communications, titled “3D atomic-scale metrology of strain relaxation and roughness in Gate-All-Around transistors via electron ptychography.”
